But is there a better open air case that you guys would/could recommend? Would the one that I posted support 4 cards without a problem? Does the one that I posted come with controls such as on/off/reset? Or do I need to buy a separate adapter for that as well?

Build is for a friend so I'll talk with him before pulling the trigger. It's other a $50 case flipped sideways and resting cards on top of one another - or a proper open air like that one for a little more.

Make one! I made one for about 10$ with a trip to Home depot. The motherboard is bolted on the black painted board with .75 inch risers so PSU cables can pass underneath, PSU is velcro'd to the board, psu is on top so all cables would come out of the left side. Don't read what others say about ambient heat making an open air design hot, I got stable mobo temps ~32 idle and cpu temps under 32/42 on idle/load.

I have a Rosewill Thor case right now in my garage hashing away. It has a 6870x2, 6870, and 5870 in top first --> bottom last order. I've had to change the rear fan, add a bottom 120, another front 140, and a aimed 80mm to keep everything semi cool. At this point the thing is so loud it isn't worth having it in a case. The only reason I do is that it is my main computer. The rest of my rigs are in an open aired rack that I got from Target for $20.

I have to agree that DIY rigs are the best way to go, the functionality to cost ratio can't be matched by any testbench you can purchase. I will say that I built a few rigs with this case; http://www.tweaktown.com/reviews/3509/lian_li_pitstop_t60_open_air_test_bench/index.html, I had a couple laying around that I had used for hardware testing. Works great for mining and I like how compact it is. You can find them for around $70 on ebay, but for the price you may as well put the money toward a better GPU

I have to agree that DIY rigs are the best way to go, the functionality to cost ratio can't be matched by any testbench you can purchase. I will say that I built a few rigs with this case; http://www.tweaktown.com/reviews/3509/lian_li_pitstop_t60_open_air_test_bench/index.html, I had a couple laying around that I had used for hardware testing. Works great for mining and I like how compact it is. You can find them for around $70 on ebay, but for the price you may as well put the money toward a better GPU

But you can't spread-out or raise your GPUs with any of those "stock" benches.